Snap switch



y 1950 R. E. MOORE 2,509,835

SNAP SWITCH Filed Dec. 20. 1946 2 S I1e ets-Sheet l ROBERT E. MOORE,

May 30, 1950 R. E. MOORE SNAP SWITCH Filed Dec. 20, 1946 2 Sheets-Sheet2 gvwcmim R BRT MOQRE Patented May 30, 1950 UNITED STATES PATENT OFFICEssar swr'rcn mam E Moore, salamims.- Application December 20, 1946,Serial N6. 717,567

to provide novel and improved switch mecha-' snap switch mecha- Claims.,iorzoo-s'z) single push-button style constructed in accordance with oneembodimentof my invention and nisms and operating means therefor. f

More particularly it is an object of the invene tion to provide in asnap switch mechanism a the same direction for successiveoperations of'10 thrust lever adapted to be actuated always inthe switch andincluding a movable-pivot. for

the lever and means for limiting said lever.

More particularly the travel of Y .45. .an object of the inven-- tion toprovide in a switch of the snap type a rocking yoke adapted to bemaintained by an over-center spring in either of two positions and inwhich a portion of the rocking yoke remote from its axis of rockingforms a fulcrum and mounting for an operating or. thrust lever adaptedto receive a force in a direction approximately along its axis fromsuitable'actuating means to move the yoke to activate the spring.,

Such thrust lever' may or may not carry a movable contact forming aportion of the circuit of the Switch. I

One of the important features of the invention comprises a dual use ofthe over-center spring for actuating the yoke and contact and providingthe return force for the operating member to insure it returning to itsinitial position after each operating thrust.

The switch of the present invention being particularlyadapted forautomatic operation, one of the features of the invention comprises aunique combination transformer and operating magnet for the actuatingplate of a switch constructed in accordance with the present invention,whereby remote low'voltage controls maybe resorted to for operating theswitch with .the attendant advantages. 1

invention will be more apparent to those skilled in the 'art upon aconsideration of the accompanying drawings and following specificationwherein are disclosed several exemplary embodi ments of the switchmechanism and the operating means therefor, it being understoodthat'such variations, combinations and modifications of the same may bemade as fall within the scope of the appended claims without departingfrom the v ofthe showing a single pole, double throw type:

Fig. 2 is aside elevation of the switch of Fig. 1 showingthe-relationship of the thrust lever and operating plate;

Fig. 3 is a view similar to Fig. 2 01 a second embodiment of the switchhavinga, diiferent con tact arrangement and including means forproviding operating plate return from the main Fig.4 is a section takenon line 4-4 of Fig. 3; Fig. 5 is a top plan view of the switch of Fig.3; Fig. 6 is an illustration ofa further arrangement I of thrust leverhaving unique limiting Fig. 'I is a' still further modification ofthrust lever and cooperating operating plate and contact making stops;and

Fig. 8 is a schematic showing of combined switch operating magnetandtransformers The present switches were developed in an effort to providesatisfactory forms of such switches-which reverse their contactpositions once each time the actuating'lever or button is depressed andreleased. Most such mechanisms haveinherently low mechanicalefiiciencies and hence require too great an eflort in their operation towarrant the use of low voltage actuators where desired. The mechanismsuggested for use herein as suitable embodiments of the presentinvention have mechanical emciences above.

fifty percent. This efficiency may be defined as the ratio of the energyrequired for one operation of the switch to the basic energy required toseparate the contacts to the dead-center toggle position.

- f a I I flange l4. Mounted on the frame are insulating Other andfurther objects and features of the blocks l6 and I! to which aresuitably attached contact tabs 18 and is carrying respectively thefacing contact buttons 20, 2| thereon, spaced apart as shown in Fig. 1.Movable contacts 22 carried by abent flange on the lower end of -switch,or if insulated from the thrust lever, are

connected .by a flexible p18 tionary terminal. I

Thejsnap action of the switch is accomplished by means of arockable'U-shaped yoke 25 pro!- tail to a suitable staerably formed of rigidwire having the out-turned fulcrum ends 26 pivoted respectively innotches 28 and 29 in the tab 30 in the front wall I 3 and in the backwall I 2. The wide bottom of the yoke has its center bent upwardly as at30 to provide a stud for the helical expansion spring 3| the oppositeend of which fits over stud 32 on arm 33 bent horizontal from the wallII and positioned vertically beneath the axis of pivot of the yoke.Under these conditions the spring becomes an over-center spring and willforce and hold the yoke to either side of a plane passing through itsaxis pivot and the stud 32, depending on which side of the center it isinitially placed.

To start the throw of the yoke by moving it beyond the dead-centerposition from whatever position of rest it may be in, the thrust lever23 is fulcrumed on the bottom reach of the yoke as at 35 or on anysuitable fulcrum remote from the yoke rocking axis. To insure the mainportion of the thrust lever remaining parallel to the sides of the frameand of the yoke, it has an integral arm 36 extending parallel to reach35 and carrying a tab 31, the latter being also fulcrumed on the yoke asclearly seen in Fig. 2. Rotation of the thrust lever in respect to theyoke may be limited by various means. As shown in Figs. 1 and 2 spacedstop arms 39 and 46, bent up from the sides of the thrust lever span oneof the side wires of the yoke against which they alternatively engage,as seen in Fig. 1. Thus the contacts on the lower arm of the lever serveto limit the throw of the yoke. Q 1 For movement of the thrust leversubstantially in line of its axis, resort is had to an operatingplate 42having a pair of spaced apertures 43 therein each fitting over a narrowtongue 44 extending upwardly from the back wall I2. The body of theoperating plate rests against the edge of frame wall l2 between thetongues. A narrow arm 46 extends from the plate beyond this fulcrum andis bent to provide an anchor for one end of the helical tension spring41, the other end of which is anchored from arm 48 struck out from theback wall [2. This insures the movement of the operating plate in aclockwise direction as viewed from Fig. 2, such movement being limitedby engagement of the far edge of the plate with the end face of a pushbutton 56 working through an aperture in the top wall M of the frame. I

In operation the switch contacts change position once for each time thatthe button 56 is pressed and released. Upon such pressure the plate 42moves downwardly in a counterclockwise direction and engages the upperend of thrust lever 23, forcing the latter downwardly and swinging theyoke in a clockwise direction,

the yoke limiting the movement so that the upper end of the thrust leverremains beneath the operating plate 42 ready for the next operation ofthe latter. The shoulder 5| on the side wall of the frame limits thedownward movement of the operating plate 42. Final movement of the topof 23 does not occur until 42 is released but the desired contacts arealready in engagement and only roll slightly.

The switch of Figs. 1 and 2 is not necessarily limited to the contactarrangement shown, for obviously various types of contacts may bemounted in other positions as long as at least one of them is carried bysome portion of the switch which alternatively assumes one of twopositions in which it remains until the next actuation of the pushbutton.

The switch of Figs. 3, 4 and 5 makes use of the basic features alreadydescribed and the frame construction need not be referred to morespecifically except in so far as it differs from that already described.In this arrangement yoke 25' has its right hand journal 26 considerablylonger than in the first embodiment and the fulcrum for the operatingplate 42' is so positioned that the plane of the operating plateintersects this portion 26 where it is cut away to prevent interferencetherewith, as shown at 66. The portion 6| beyond this cutout engagesbeneath the under surface of the portion 26 as clearly seen in Fig. 3,so that it holds the plate cocked up in the position illustrated againstthe under face of push button 56. When plate 42' is depressed, portion6| engages beneath 26 and lifts the whole side of the yoke sufficientlyto compress the overcenter spring 3|, which thereby acts not only forits designated purpose but to maintain and return the operating lever toits upper position, thus dispensing with the operating plate spring 41of Fig. 1.

In the second embodiment of the switch the over-center spring 3| bearsagainst the bottom reach of the yoke, but its upper end, instead ofengagin a stationary stud on the frame, is mounted over a nub portion 62in the inner horizontal arm SI of a wire stirrup having a substantiallyvertical arm 64 offset therefrom by portion 65. Arm 64 merges into ahorizontal portion 66 at the bottom which bears in a pair ofindentations 61 in spaced cross strips 68 stamped out from the bottomwall 69 of the frame. The

outer horizontal arm 63 of the stirrup extends.

parallel to the axis of oscillation of the yoke and forms a bridgingmember adapted-to engage the spaced contact springs 16 mounted on aninsulating block H carried by arm 12 of the frame. It thus bridges themto close the circuit. These contacts likewise act as a stop limiting theswinging of the stirrup under the action of spring 3! as viewed in Fig-1, until the over-center spring to the position shown in Fig. 4.Movement of takes control and moves the yoke to its opposite position asdetermined by contact and stop on the lever, which partakes of a partialcounterclockwise rotation.

An important feature of the arrangement is the sliding and rockingmotions given to the movable contacts in respect to stationary contactsat the time of initiating movement of the switch parts, thus insuringthat the contacts are free to separate when the spring takes control. Asthe spring swings the yoke over, contact 22 makes engagement withcontact 26 and further movement of the yoke rotates thelever 23 in acounterclockwise direction as seen in Fig. 1 until stop stirrup 64 inthe opposite direction when the yoke is swung over is limited by stop13.

Thrust lever 23', which is preferably pivoted to the bottom element ofthe yoke, as in the earlier embodiment, carries stop lugs 39 and 46' toengage with the yoke side element, but since there are no contacts tolimit the movement of the lower end of this lever it is provided'withspaced tines 15 and I6 straddling the bottom horizontal pivot portion 66of the stirrup, which acts as a stop for one or the other of them,depending on the position of the thrust lever and thus limits the swingof the yoke.

In the operation of this embodiment an addi- 40 comes into engagementwith the side arm of tional movable element is made use of to carry themovable contact; and it is actuated by the opposite end of theover-center spring. By this construction the contacts are completelyremoved from any possible manipulation by the operator which might causearcing and are solely under control of the spring.

In Fig. 6 is illustrated a further embodiment of the thrust lever 23capable of use with either type of switch shown in the first twoembodiments. It is shown as fulcrumed on the yoke element of 25 as inthe previous embodiments and is provided with upper and lower lateralstop arrangements to limit its movement, one of which may be replaced bycontacts. Thus the lower end is narrowed to a tongue I working in slotIII in the bottom wall of the frame, the ends of which slot limitlateral movement of the lever. The upper end is likewise provided with atongue I" working in slot I01 in the operating plate. The shoulders I020r I03 on the lever are selectively engaged by the lower surfaces I04 orI05 of the operating plate to impart thrust to the lever, while tongueI06 working in the slot selectively engages the ends of the slot tolimit lateral movement of the top portion of the thrust lever. With thisarrangement no stops are needed between the yoke and lever to limitrelative movement therebetween.

In Fig. 7 the thrust lever 28 is arranged, at the bottom, the same asthe one in Fig. 6. Top lateral stops are composed, at one side, ofengaging contacts I08 and I I0 and the side of the lever and abutment H2stamped from the wall of the frame on the other. In this constructionthe operating plate 42 is provided with companion indentations H5 and H6above the respective stationary positions of the tip ill of lever 23serving to prevent lateral travel of the upper end of the thrust leverwhen it is being pushed downwardly before the spring takes over, so thatthe contacts will not bind excessively but will be slid to insure theirbreaking loose and to keep them wiped clean.

Manifold economies may be effected in the wiring of buildings and housesby arranging control switches adjacent the apparatus which they controlor at some point in the wiring system not requiring any excessworking-voltage conductors and operating them remotely through lowvoltage circuits. This eliminates the need for large quantities ofinsulated and protected cable or conduit running to switches at distantpoints. The low. voltage conductors can be relatively small in size andhave only nominal insulation. Conduit boxes would not be required forsimple momentary contact push buttonswitches in control of these lowvoltage conductors.

Fig. 8 shows a simple magnetic means for actuating the operating plate42 of any of the switches hereto described. Low voltage for theoperating circuit is developed by a transformer 200, the magneticcircuit of which includes a closed core 2M and an L-shaped'extensionportion 202 and 203, on the upper free end of which the fulcrum for thecombined plate and armature 42 is provided. A high voltage winding 204passes through the window of the core 2M and is energized from the highvoltage power source continuously. A low voltage winding 205 likewisepasses through the window and ma be wound on the same or another leg ofthe core, and is connected to a control switch 206 by low voltageconductors 201.

In operation, with the circuit of 200 open, the magnetizingilux in thecore is lnsufllcient to create enough flux in the air gap at 200 toattract the operating plate 42. When, however, the circuit of winding205 is closed, the voltage induced in this winding causes a current flowtherein producing a magneto-motive-force opposing that generated bywinding 204, causing the current in this latter coil to increase tomaintain the flux at its equilibrium value. The increased flux in thecore is partially shunted to the air gap resulting in sufficientattraction to draw down plate 42 and operate the switch (not-shown)which may be mounted in the arms of the core L. Release of the pushbutton 206 opens the low voltage winding circuit and the core flux dropssumciently for the armature attraction to be overcome by the spring 41whereby plate 42 is lifted and made ready for the next operation of theswitch. The amount of current used by primary winding 204 isinconsequential and usually insufllcient to operate the meter.

I claim:

1. In a switch .of the type described, in combination, a frame, anactuator adapted to be moved and returned for each opening and for eachclosing of the switch, a yoke mounted for rocking on said frame, anover-center spring having one end bearing on said yoke and the oppositeend supported independently of said actuator, a thrust lever journalledon a portion of the yoke remote from its axis of rocking and extendingpartially between the yoke arms, said lever being arranged fortransmitting thrust from the actuator to move the yoke from eitherposition of rest sufficiently to start the spring over-center and tothen cross the axis of rocking of the yoke when the actuator isreturned, a stationary contact carried by said frame, and a secondcontact carried on one of the movable parts of the switch.

2. In a switch of the type described, in combination, a frame, a yokemounted for rocking on said frame, an over-center spring having one endbearing on said yoke, a thrust lever journalled on a portion of the yokeremote from its axis of rocking and extending partially between the yokearms, said lever being arranged for transmitting thrust to initiallymove the yoke from either position of rest sufficiently to start thespring over-center, a stationary contact carried by said frame, a secondcontact carried on one of the movable parts of the switch, cooperatingmeans on and limiting relative rotation of the yoke and lever and meansforming a stop for said lever opposite its journal from the saidcooperating means.

3. In a switch of the type described, in combination, a frame, a yokemounted for rocking on said frame, an over-center spring having one endbearing on said yoke, a thrust lever journalled on a portion of the yokeremote from its axis of rocking and having a portion extending betweenthe yoke arms and beyond the axis, a plate rockably mounted on saidframe, said lever being arranged for transmitting thrust from said plateto initially move the yoke from either position of rest sufilciently tostart the spring over-center, a stationary contact carried by saidframe, a second contact carried on one of the movable parts of theswitch, means limiting relative rotation of the yoke and lever, andmeans limiting transverse movement of the lever.

4.'A snap switch assembly including a frame structure, a yoke mountedfor rocking on said frame about an axis, an over-center spring arrangedbetween the frame and yoke to control the position of the latter, athrust lever journalled on said yoke about a second axis parallel to andremote from said first axis, said lever having a portion extending inthe general direction of the. first axis, means limiting relativerotation of the lever and yoke, means including said spring to alwaysposition said lever portion to the same side of a plane through the saidfirst axis of the yoke bisecting its angle of throw as the yoke ispositioned, an operating plate adapted to be moved generally in theaxial direction of said lever to impart a thrust to the said portion ofthe same and contacts fixed respectively to the frame and a movable partof the switch assembly.

5. The snap switch assembly as defined in claim 4 in which the operatingplate is fulcrumed to the frame structure for movement about an axis at.

right angles to that of the yoke.

6. The snap switch assembly as defined in claim 4 in which the operatingplate is fulcrumed to the frame and means associating said plate andyoke whereby said spring retracts the plate upon release after actuatingsaid lever. l

7. A snap switch including a frame, a yoke pivoted for swinging in saidframe about an axis, a stirrup pivoted for swinging in said frame aboutan axis parallel to and remote from said first axis, an over-centerspring compressed between parts of said yoke and stirrup each remotefrom its axis, stops limiting movement of said stirrup, one of saidstops comprising a stationary contact, a thrust lever pivoted to saidyoke remote from the axis of the latter, a portion of the leverextending generally toward the yoke axis, and means including the springcausing the said portion to assume a position divergent to the plane ofsaid yoke and on the opposite side thereof from the spring,

8. The switch as defined in claim 7 in which said last mentioned meansalso include stops limiting relative motion of the yoke and lever.

9. The switch as defined in claim 7 in which said last mentioned meansalso include stops limiting relative motion of the yoke and lever andstops limiting movement of theyoke in respect to the frame.

10. A snap switch mechanism including a frame, a yoke pivoted forswinging in said frame, an over-center spring effective between theframe and yoke, a lever journalled intermediate its ends to a portion ofthe yoke remote from its pivots, spaced means on said frame to bealternatively engaged by one end of said lever to limit its transversemotion, means on said frame to be alternatively engaged by the other endof the lever to limit its transverse movement, and anactuating plateadapted to impart thrust to the last mentioned end of the lever ineither of its stopped positions.

11. A snap switch mechanism as defined in claim 10 in which the lastmentioned lever end and the actuating plate are provided withinterfitting means at the said position.

12. The switch as claimed in claim 1 in which a stirrup fulcrumed to theframe remote from the yoke axis supports the opposite ends of thespring, said movable contact being mounted on said stirrup.

13. A snap switch including a frame, a yoke 8 pivoted for swinging insaid frame about an axis, a stirrup pivoted for swinging in said frameabout an axis parallel to and remote from said first axis. anover-center spring compressed betweenparts of said yoke and stirrup eachremote from its axis, stops limiting movement of said stirrup, one ofsaid stops comprising a stationary' contact, a thrust lever pivotedtosaid yoke remote from the axis of the latter, a portion of the leverextending generally toward the yoke axis, means including the springcausing the said portion to assume a position divergent to the plane ofsaid yoke and on the opposite side thereof from the spring, said stirrupcomprising the other contact and means limiting the relative rotationalmovement of lever and yoke.

14. A snap switch mechanism including a frame, a yoke pivoted forswinging in said frame. an over-center spring effective between theframe and yoke, a lever journalled intermediate its ends to a portion ofthe yoke remote from its pivots, spaced means on said frame to bealternatively engaged by one end of said lever to limit its transversemotion, spaced means on the opposite end of the lever to alternativelyengage the yoke to limit relative movement of the lever thereto, anactuating plate adapted to impart thrust to the last mentioned end ofthe lever in either of its stopped positions, a contact carried by andinsulated from the frame and an engaging contact movable relativethereto under the action of said yoke.

15. In a switch of the type described, in combination, a stationaryframe, a movable member mounted for rocking on said frame about an axis,a movable thrust lever pivoted on a portion oi said rocking memberremote from its axis oi rocking, an over-center spring bearing on one ofthe movable parts at a point remote from the said axis, said thrustlever being arranged for transmitting thrust for compressing the springto initially move the rocking member from either position of restsufliciently to start the spring over center, a stirrup pivoted on saidframe on an axis parallel to and remote from the axis of rocking of saidmember, the opposite end of said spring being mounted on the stirrupremote from its axis, a contact carried by a. part of the stirrup, and acooperating contact carried by said frame. ROBERT E. MOORE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

